warp.spatial\_dot
=================

.. currentmodule:: warp._src.lang

.. function:: spatial_dot(a: Vector[Float, Literal[6]], b: Vector[Float, Literal[6]]) -> Float

   .. wp-function-tags::
      :kernel: true
      :python: true
      :differentiable: true

   Return the dot product of two 6D spatial vectors.
   
   A wrench dotted with a twist gives instantaneous power. Both arguments must have the same
   scalar type.
   
   :param a: First spatial vector.
   :param b: Second spatial vector.
   
   :returns: The dot product, as a scalar of the same type as the arguments.
   
   .. rubric:: Example
   
   .. testcode::
   
       @wp.kernel
       def compute_power(
           twists: wp.array[wp.spatial_vector],
           wrenches: wp.array[wp.spatial_vector],
           out: wp.array[float],
       ):
           i = wp.tid()
           out[i] = wp.spatial_dot(wrenches[i], twists[i])
   
       # spinning at 2 rad/s about z under a torque of 3 N.m about z
       twists = wp.array([wp.spatial_vector(0.0, 0.0, 2.0, 1.0, 0.0, 0.0)], dtype=wp.spatial_vector)
       wrenches = wp.array([wp.spatial_vector(0.0, 0.0, 3.0, 0.0, 0.0, 0.0)], dtype=wp.spatial_vector)
       out = wp.empty(1, dtype=float)
       wp.launch(compute_power, dim=1, inputs=[twists, wrenches], outputs=[out])
       print(out.numpy())
   
   .. testoutput::
   
       [6.]